Saga of a Tata Altroz Diesel with DPF problems

For Tata cars, the soot load value is normally at 60%. Anything above would require some spirited driving to clear the diesel particulate filter.

BHPian Shanksta recently shared this with other enthusiasts.

Hi All,

An update on this issue might be useful for fellow BS6 diesel/Altroz diesel owners.

So yesterday my friend took his car to Kaveri Tata in Trichy as requested by TASS. Around evening he called me and requested me to talk to the Service advisor as what he was saying did not make sense to him. Post my conversation with him and some additional Googled knowledge below is what I could make of this entire ordeal.

A DPF-equipped vehicle has a sensor that monitors the "soot load" in the DPF.

Typically this Soot load is calculated mostly from 0%-250%.

For Tata, the normal soot load value is 60% or lesser. Anything above this the car requests you to drive spiritedly to clear the DPF as we all know.

When this initial warning is ignored the soot load increases, now there is also a preset limit by the manufacturer to ensure the car does not cause harm to itself when the soot load increases. This is because the soot load increase causes stress on the exhaust system thereby increasing the heat considerably.

When this happens the car is programmed to jump into "Limp mode", which is what my friend experienced.

My friend's Altroz DPF was measured and the soot load was at 138% as told to me by the SA. When this preset limit is breached the sensors/ECU are programmed to throw the "Check Engine light" and the "Service Station Symbol".

Now, this requires a "Recovery Regeneration" cycle to be performed by Tata Service Center. They follow a standard procedure where the engine has to cool down, then they reset the error codes and drive the car at the requested rpm to clear the soot and also this recovery Regeneration requires them to check the temperature of the engine oil, its condition and the oil filter.

Once this is done they have to TD the car again and reset codes if any. Finally, measure the soot load once again. One good thing though is the service advisor has clearly told him that he will not be charged a single rupee, however need to confirm this when he picks up the car today.

So basically my friend did not notice the first warning on the cluster to clear the DPF and this has caused this entire saga.

One of the websites that really helped me understand this process is here.

Owning a BS6 diesel is no joke!

Here's what BHPian Nikhil Beke had to say on the matter:

Didn't you say 80% of his 9k km were on the highways? Why did the soot levels rise so much, (sufficient to clog the DPF) in the first place? What else is an owner supposed to do, to prevent clogging?

Anyway, agree with the sentiment that one would have to go through a lot of trying times, owning this fabulous engine. That further hardens my resolve of stepping away from diesel (would opt for iTurbo, maybe). One can't keep on having this hanging sword over one's head. And then there would be additional sensor malfunction and other additional electronic niggles: remember we're just in the first year of ownership.

BTW - how long is this 'not a single penny charged' going to continue? If there are too many such incidents, the service centres would have to employ additional staff for this entire process.

Here's what BHPian akshay380 had to say on the matter:

When I last checked the soot load, it was 14.8% after 5,100 km. Now I'm at 6,200 km and will be visiting SC today for the second service. Will note down the readings and report.

Aside from this, I believe people have to buy diesel only if it fits their use cases. I drive 50-50 in the city and two-lane Goan highways choked with traffic and make it a point to at least drive 15min at slightly higher rpm which pushes the engine temperature up. Will only know if this works but unlike my friend who drives exact same route and kept getting errors from 3,000 km, I have not got anything.

Here's what BHPian rd18 had to say on the matter:

Yes, very useful. I wonder if such a % can be shown in the instrument cluster. Would relieve a lot of owners, who may be worried about DPF light ON anytime and possibly miss it. Peace of mind.

Check out BHPian comments for more insights and information.